Different ionization processes can be identified by measuring the full momentum vectors of coulomb exploding N+ or O+ fragments in coincidence using COLd Target Recoil Ion Momentum Spectroscopy (COLTRIMS). We measured hi

Different ionization processes can be identified by measuring the full momentum vectors of coulomb exploding N+ or O+ fragments in coincidence using COLd Target Recoil Ion Momentum Spectroscopy (COLTRIMS). We measured high resolution kinetic energy release spectra and show angular dependences for double ionized N2 and O2 molecules with laser peak intensities between 1 and 20E14 W/cm2. We find that the process proceeds through well defined electronic states of the excited molecular dications. Using linear and circularly polarized light, we identify two mechanisms for the production of theses states, rescattering and sequential ionization. By using 8 fs pulses, we observe that the internuclear distance can be frozen during the pulse.